1. Field of the Invention
The present invention relates generally to an apparatus for refining operations, and more particularly, but not by way of limitation, to furnace systems having vertically-oriented radiant sections.
2. History of the Related Art
Delayed coking refers to a refining process that includes heating a residual oil feed, made up of heavy, long-chain hydrocarbon molecules, to a cracking temperature in a furnace system. Typically, furnace systems used in the delayed coking process include a plurality of tubes arranged in a multiple-pass configuration. Often times, a furnace system includes at least one convection section and at least one radiant section. The residual oil feed is pre-heated in the at least one convection section prior to being conveyed to the at least one radiant section where the residual oil feed is heated to the cracking temperature. In some cases, design considerations dictate that the furnace system include multiple convection sections and multiple radiant sections. Such an arrangement requires an area of sufficient size in which to place the furnace system.
In some cases, space constraints limit the number of radiant sections that can be placed in a side-by-side arrangement in a given area. This results in the furnace system being constructed with less than an ideal number of radiant sections. Thus, it would be beneficial to design the furnace system to allow placement of multiple radiant sections or convection sections in a smaller area.
U.S. Pat. No. 5,878,699, assigned to The M.W. Kellogg Company, discloses a twin-cell process furnace utilizing a pair of radiant cells. The pair of radiant cells are arranged in close proximity to each other in a generally side-by-side orientation. An overhead convection section is placed above, and centered between the pair of radiant cells. Combustion gas is drawn into the convection section via induced and forced-draft fans. The twin-cell process furnace requires a smaller area and allows increased flexibility in heating multiple services and easier radiant tube replacement.